Ultrasonic Transducer Backing Structure Acoustic Reflection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piezoelectric acoustic transducers face challenges in efficiently managing thermal and acoustic energy, leading to performance limitations and inefficiencies.
Innovation Solution
The ultrasonic transducer incorporates a thermally and electrically conductive backing structure with dual layer de-matching backings, a heat sink, and electrodes, optimized for acoustic impedance and thickness to reflect and disperse energy effectively, while incorporating a heat transfer system for thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional backing structure is used, then the transducer structure is simple, but thermal energy cannot be effectively managed and acoustic energy is not efficiently reflected
Solution Approach 1:
The backing structure is segmented into multiple functional layers including a thermally conductive layer for heat dissipation, an acoustically transparent layer for energy reflection, and de-matching layers for acoustic impedance optimization. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between thermal management and structural simplicity.
Solution Approach 2:
The patent employs composite material construction with layers of different materials (e.g., tungsten, copper, graphite, epoxy) each selected for specific thermal and acoustic properties. This composite approach enables simultaneous optimization of thermal conduction and acoustic reflection without requiring a single complex material, thus managing thermal energy effectively while maintaining reasonable structural complexity.
2Speed
If the piezoelectric material is made thick to achieve half-wave resonance, then the operational frequency is improved, but the transducer size increases
Solution Approach 1:
The patent applies local quality optimization by using a thick piezoelectric material specifically at the resonant frequency location to achieve half-wave resonance, while keeping other components compact. The backing structure and de-matching layers are locally optimized to reflect acoustic energy back through the piezoelectric material, maintaining the resonant frequency response without requiring the entire transducer assembly to be large.
Solution Approach 2:
The patent addresses the size-frequency contradiction by optimizing the backing structure in the dimensional space behind the piezoelectric material. The de-matching layers and thermally conductive backing create an acoustic environment that effectively extends the resonant behavior without increasing the front-facing dimensions of the transducer, thus improving frequency response while controlling overall size.
3Temperature
If a thermally conductive backing structure is used, then thermal management is improved, but acoustic impedance matching becomes more difficult
Solution Approach 1:
The patent introduces de-matching layers as intermediary structures between the piezoelectric material and the thermally conductive backing. These intermediary layers with specific acoustic impedance values (e.g., tungsten layer with 100 MR, graphite layer with 5.1 MR) serve as acoustic transformers that facilitate impedance matching while allowing the backing structure to maintain its thermal conduction function. This intermediary approach resolves the contradiction between thermal management and acoustic impedance matching.
Solution Approach 2:
The patent optimizes the thickness and material composition parameters of the de-matching layers to achieve the desired acoustic impedance transformation. By carefully selecting layer thicknesses (e.g., quarter-wavelength at operational frequency) and material properties, the system achieves both thermal conduction through the backing and acoustic impedance matching through the layered structure, resolving the parameter optimization contradiction.
4Reliability
If de-matching layers are added to reflect acoustic energy, then acoustic performance is improved, but the device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing the de-matching layers and thermally conductive backing to serve multiple purposes simultaneously. The same layered structure provides acoustic impedance matching, acoustic energy reflection, and thermal conduction pathways. This universal design approach improves acoustic performance while minimizing the increase in device complexity by avoiding separate dedicated structures for each function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances acoustic performance by reflecting energy in phase and dispersing unwanted reverberations, while effectively managing thermal energy, thereby improving the transducer's operational efficiency and durability.
Implementation Method 1
Piezoelectric ultrasonic transducers change electrical energy into mechanical energy, and reciprocally convert acoustic waves into electrical signal(s)
Implementation Method 2
a backing structure positioned at the back surface of the piezoelectric material and configured to reflect acoustic energy towards the front surface of the piezoelectric material
Implementation Method 3
a heat sink in thermal contact with the backing structure
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2
AI summary
There is provided an ultrasonic transducer having a sample-contacting portion and a back portion, the back portion being opposed to the sample contacting portion. The transducer includes a piezoelectric material configured to be in acoustic communication with a sample and a backing structure in acoustic communication with the piezoelectric material. The backing structure is configured to reflect acoustic energy towards the sample-contacting portion and away from the back portion of the ultrasonic transducer. The backing structure includes a low acoustic impedance layer and a high acoustic impedance layer. The transducer may also include a second dual layer de-matching backing. The second dual layer de-matching backing includes a second low acoustic impedance layer and a second high acoustic impedance layer. There are also provided ultrasonic transducers including a one-dimensional piezoelectric array or a two-dimensional piezoelectric matrix and including backing structure configured to reflect acoustic energy.